Radiators

Start thinking about next summer's heat issues while sitting in front of the fireplace

Tips from Hemmings Muscle Machines

In many parts of the country, January is probably not the time you sit around contemplating what to do about your fair weather muscle car's cooling system. But then again, maybe it's the best time to do that kind of thinking. Without the time constraints of attending cruise-ins or car shows, during the winter you can address those summer overheating issues and have your car all ready for next cruising season.
One of the easiest ways to solve a boil-over problem or a situation where your car tends to run too hot is to repair or upgrade your radiator. This month, we contacted several radiator manufacturers to see what options were available to improve your cooling system, whether you just want to recore your existing unit, find a direct bolt-in replacement radiator or find a higher-efficiency aftermarket product that will help your engine stay cooler.
For this month's installment, in order to compare like products, we chose to ask suppliers about options for a 1967 Corvette with manual transmission and the 427-cu.in. four-barrel L-36 engine. Engine horsepower is always a consideration when upgrading your radiator, and there were several options available in the 1967 Corvettes; however, the L-36 was the base 390hp or 400hp when carbureted by triple two-barrel Holleys. If your Corvette is putting out more horsepower than that, a larger-capacity radiator should be considered. The original radiator core for this application was a four-core unit and the core size was 17 inches by 22½ inches and 2-5/8 inches thick.
Cool Craft Components has several options available for this Corvette application. A replacement copper and brass bolt-in radiator for our example car is offered with a high-efficiency Desert Cooler core through its US Radiator division. These cores use ½-inch tubes on 3/8-inch tube centers with serpentine fins to provide more tube-to-fin bond area than a conventional core that uses ½-inch tubes on 9/16-inch centers. This means the radiator will transfer more heat and there will be a larger temperature drop between the coolant at the inlet header and the outlet header. Cool Craft's replacement unit (#010810) sells for $707.
Optional offerings include an Optima core featuring ½-inch tubes on 5/16-inch centers, which provides even more cooling surface. Cool Craft aluminum two-row racing cores are also available with one-inch tubes and TIG-welded tanks. Both the US Radiator Desert Cooler and Optima radiators and the Cool Craft aluminum units can be ordered with the Triple Flow tank option. Triple Flow routes the coolant through the radiator core three times by adding additional walls within the inlet and outlet tanks, resulting in up to a 15 percent increase in the radiator's cooling ability.
Probably the best-recognized supplier of radiators among Corvette enthusiasts is DeWitt's Radiators. Well-known for its concours restoration-quality copper radiator cores, DeWitt's also offers several radiator upgrades. For originality, DeWitt's sells a reproduction unit (#BC67M) that is 100 percent correct for show judging and includes factory-specific channels with both rectangular and round holes, plus the authentic Harrison name embossing. This reproduction unit sells for $695.
If you are looking for an aftermarket upgrade radiator, DeWitt's offers a two-row aluminum radiator that will replace your existing four-row while delivering higher efficiency. The replacement unit (#A66M) will provide 25 percent more cooling capacity than the original radiator. No modifications are necessary to install this unit; factory inlets and outlets are the same as are the factory channels and end tanks. Unpainted, this aluminum replacement radiator retails for $495, although you can request a black epoxy paint finish for an additional $30.
Dewitt's also owns the original GM tooling and is licensed to manufacture OEM replacement radiator cores. These cores can be installed onto your own original tanks at many radiator recore businesses. The core (#BC-2) is concours-correct for all 1966-'68 Corvette big-blocks, as well as the 1968 small-block automatic, and sells for $340.
Direct Fit radiators are a registered trademark of DeWitt's, which also offers an aluminum Direct Fit for this application. This bare aluminum radiator (part# 942B, $795) can be easily installed in place of your OE brass/copper radiator and will provide 4,600 BTUs of cooling, a substantial 1,300 BTUs more than the stock radiator.
For maximum cooling, DeWitt's offers a replacement 23-inch aluminum-core radiator equipped with dual SPAL 11-inch electric fans. Part number SP022 includes a new wiring harness to install the system, which will bolt right into your existing 1967 radiator mounts and eliminates both the original fan shroud and belt-driven fan, resulting in a slight horsepower increase. This complete assembly retails for $920.
Classic Radiators is a full-service radiator repair shop that offers a re-coring service for all muscle car radiators as well as heater cores. Classic Radiator has done many concours-quality radiator restorations and can install replacement cores in your Corvette radiator; it can also ensure correct placement of the original identification tags.
For aftermarket replacement radiators, Classic Radiators offers US Radiator aftermarket copper/brass units and Griffin, Be Cool and Flex-A-Lite aluminum radiators, as well as other cooling system replacement parts. For our example Corvette, Bill Carberry at Classic Radiators recommends either a US Radiator copper/brass replacement unit or a Griffin aluminum aftermarket unit as an alternative to restoring the original copper/brass.
Griffin Radiators come with a two-year warranty and are available in two-row with one-inch diameter or 1¼-inch diameter tubes. Griffin also markets a performance radiator for Corvettes producing more than the stock horsepower, with two offerings rated for engines up to 600hp.
Flex-A-Lite radiators are manufactured with aluminum tanks designed to dissipate heat 300 percent better than conventional brass tanks. Several universal 22-inch by 18-inch core configurations are available to custom-design a replacement cooling system. Flex-A-Lite also produces quality flex fans, recovery tanks and electric pusher fans that allow you to build your own radiator, fan shroud and fan replacement system.
Be Cool Radiators has several Corvette replacement radiators available. Be Cool radiators are 40 percent lighter than an OE radiator and, because of their three-inch thickness, allow for an additional 20 to 40 degrees of cooling over a stock configuration radiator. They are available in both 28 x 19-inch or 27 x 17-inch core sizes. For 1963-'68 Corvettes, both natural and polished finishes are available. Pricing ranges from $499 to $749.
Because of the width of these units, some fan-shroud modification will be necessary and the top radiator hose will have to be changed. In addition, these radiators will have to be mounted to a small-block radiator core support. These units are great for installing on engine swaps when changing from a 327 or 350 to a 396 or 427.
Although Griffin, Be Cool and Flex-A-Lite have many Corvette radiators available, they usually sell their products through a dealer network and not directly to the enthusiast. Classic Radiators has all these products available or you can contact these companies directly to be find one of their dealers near you.
Mattson's Radiator is a radiator repair facility that will recore your existing radiator back to factory specifications. It has the ability to repair both copper and aluminum radiators and can custom-design aftermarket aluminum replacement radiators; the company can also make radiator and A/C condenser combination units. Mattson's carries SPAL electric fan assemblies and fan shrouds to complete your custom Corvette cooling system.
Ron Davis Racing Products produces a performance aluminum radiator for 1966-'68 Corvettes that is used for racing applications in engines rated up to 700hp. This racing radiator (#1-16CV6668) uses a two-row core with one-inch diameter tubes. Ron Davis radiators are all aluminum, pressure tested and TIG-welded with billet aluminum fittings and multi-louvered fins. Electric fans and aluminum shroud assemblies are offered, as are add-on transmission and engine oil coolers.
Santa Monica Auto Radiators can also recore Corvette radiators. Chuck Perliter at Santa Monica recommends contacting DeWitt's for a concours-quality restoration unit; however, besides being able to rebuild your old unit, Santa Monica can provide custom-built units based on a Ferrari design. Chuck says this Ferrari design is one of the most efficient heat transfer systems he has come across and the company has used it to build many custom radiators for special applications. Contact Santa Monica Auto Radiator with your radiator dimensions for further details.
As with all system upgrades, a radiator will only work as well as the other components in the system will allow. Consider the water pump, radiator cap, thermostat, cooling fan and radiator hoses--these are all other items that can increase cooling system efficiency. With air conditioning-equipped vehicles, the fan-clutch assembly and air-conditioning condenser should also be considered, especially since they will be removed during radiator replacement anyway. Proper maintenance of your antifreeze will also help in keeping your car cool in the summer.
With all the different possibilities highlighted this month, it's clear that this is a great time of year to sit down and create a plan of action for improving your cooling system before next spring. Whether you are keeping your Corvette all-original for the show season or you're planning to take it to the race track next summer, now is the time to start getting it ready.
One of the refreshing things we discovered in researching this article is that each of these vendors has a very knowledgeable staff and can offer detailed technical assistance to help you decide which unit fits your cooling-system needs. So do some research on your own or use these resources to help you decide what will work best for you.
SourcesCool Craft Components Inc. U.S. Radiator Corporation
323-826-0965www.coolcraft.comDeWitt's Corvette Radiators
517-548-0600www.dewitts.comClassic Radiators
516-293-9026www.caparadiator.comMattson's Radiator
714-826-0357www.mattsonsradiator.comRon Davis Racing Products
623-877-5000www.rondavisradiators.comSanta Monica Auto Radiators
310-395-2196www.santamonicaradiator.comBe Cool Incorporated
800-691-2667www.becool.comFlex-A-Lite
866-447-5967www.flex-a-lite.comGriffin Radiators
800-722-3723www.griffinrad.comSPAL USA
800-345-0327www.spalusa.com

This article originally appeared in the January, 2009 issue of Hemmings Muscle Machines.